The present invention relates to an automatic document feeding device for an electrophotographic copying apparatus. More particularly, the present invention relates to a reversing-type automatic document feeding device (RADF) capable of feeding an original document to a predetermined position of a transparent platen of the copying apparatus, guiding the original thus fed to an original reversing section to reverse the original, and feeding the original again to the transparent platen.
Recently, a demand for a multi-functional electrophotographic copying apparatus has become strong. As a part of such a demand, there has been proposed a copying apparatus provided with a function of forming copied images on both sides of a piece of copying paper, or a function of carrying out a plurality of copying operations on at least one side of copying paper (See, for example, Unexamined Japanese Patent Publication 77454/1984).
Such a copying apparatus is provided with a basic function of discharging, after a normal copying operation has been carried out, copying paper on which the image of an original has been fixed, as it is, to a receiving tray. In order to carry out a plurality of copying operations on the same copying paper, the copying apparatus is further provided with a function of guiding copying paper on which the image of an original has been fixed, again to a copying section along a curved guide which is formed inside of the copying apparatus body.
On the other hand, an electrophotographic copying apparatus having a function of forming original images on both sides of a piece of copying paper, is generally provided with an RADF which is not only capable of automatically feeding a both-sided (duplex) original from an original feeding section to a transparent platen, but also capable of reversing the original such that the original of which one side has been scanned and exposed, is copied at the other side thereof (See, for example, Unexamined Japanese Patent Publication 163959/1983).
In such an RADF, a loop-like original reversing section for reversing the original, is disposed in a continuous manner from an original delivering section of the belt delivery type opposite to the transparent platen. According to this RADF, a both-sided original fed from the original feeding section is fed to the transparent platen at a predetermined position thereof by the original delivering section. Upon completion of the scanning and exposure of one side of the original thus fed, the original is fed to the original reversing section by the original delivering section. After reversed, the original can be fed again onto the transparent platen.
In view of the demand for a multi-functional copying apparatus mentioned earlier, the inventors have tried to add a function of respectively copying the obverse and reverse sides of a both-sided original on the same copying paper at its left- and right-half portions so that the the copied paper will be a double truck, to a copying apparatus provided with a function of carrying out a plurality of copying operations on at least one side of copying paper.
In the RADF mentioned earlier, when feeding an original to the transparent platen from the original feeding section, and later from the original reversing section, the original is fed to the transparent platen at the same position thereof. Accordingly, even though this RADF is mounted on the copying apparatus above-mentioned, the copying apparatus as it is cannot copy, respectively, the obverse and reverse sides of a bothsided original on the same copying paper at its rightand left-half portions so that the copied paper will be a double truck.
More specifically, even though copying paper twice the size of a both-sided original is fed to a copying section having a photoreceptor drum and the like, and two copying operations are respectively tried to be carried out on the right- and left-half portions of this copying paper, the original before and after reversing is fed to the transparent platen at the same position thereof. This results in double copyings of images on the obverse and reverse sides of the original, on the same half-portion of the copying paper. It is therefore not possible to add the function above-mentioned to such a copying apparatus. Accordingly, the RADF of the type above-mentioned cannot easily comply with a demand for a multi-functional copying apparatus.
It is an object of the present invention to provide an RADF capable of respectively copying the obverse and reverse sides of a both-sided original on the same copying paper at its right- and left-half portions so that the copied paper will be a double truck, which can be additionally mounted on an electrophotographic copying apparatus provided with a function of carrying out a plurality of copying operations on at least one side of copying paper.
The RADF in accordance with the present invention comprises:
an original reversing section for introducing an original on a transparent platen to reverse the same;
an original delivering section for delivering the original as fed from an original feeding section and as reversed by the original reversing section while the original is held by and between the transparent platen and the original delivering section;
first original detector means for detecting that the original has been fed from the original feeding section to the original delivering section;
second original detector means for detecting that the original reversed by the original reversing section, has been fed to the original delivering section; and
drive control means for controlling the drive of the original delivering section such that, in response to an original detection signal supplied from the first original detector means, the original is fed to the transparent platen at a first feed position thereof, and such that, in response to an original detection signal supplied from the second original detector means, the original is fed to the transparent platen at a second feed position thereof adjacent to the first feed position above-mentioned.
In accordance with the RADF arranged as above-mentioned, the first original detector means detects that the original has been fed from the original feeding section to the original delivering section, and in response to an original detection signal supplied from the first original detector means, the drive control means drives the original delivering section to feed the original to the transparent platen at the first feed position thereof. The second original detector means detects that the original reversed by the original reversing section has been fed to the original delivering section, and in response to an original detection signal from the second original detector means, the drive control means drives the original delivering section to feed the reversed original to the transparent platen at the second feed position thereof adjacent to the first feed position.
The object of the present invention above-mentioned will be more apparent from the following detailed description with reference to the attached drawings.